Backlash is an inherent property of lead screw assemblies due to the sliding motion between the screw and the nut. For some applications, a certain amount of backlash, or “play,” can be tolerated, but applications such as positioning, dispensing, or assembly often require a level of precision and repeatability that can’t be achieved if backlash […]
Ball + lead + roller screws
What’s the difference between ball screw critical speed and characteristic speed?
Ball screw drives incorporate two primary moving components: the rotating screw shaft and the nut that traverses the screw. (The radial bearings that support the screw shaft play a minor role for the purposes of this discussion.) This means that to accurately determine the maximum allowable speed of a ball screw assembly, there are two […]
What is a follower nut, and what role does it play in lead screw operation?
Although the idea of a “follower nut” may seem to indicate that the nut serves a passive role in lead screw operation, it actually plays an important part in monitoring the condition and life of the screw assembly. The wear characteristics of a lead screw nut make the expected service life of the assembly difficult […]
When to use linear bearings and ball nuts with ceramic balls
Ball nut preload: What effect does it have on bearing life?
Ball nut preload offers several benefits to screw assemblies, but the most common reason for using a preloaded ball nut is to reduce axial play, or backlash, caused by clearance between the screw and nut raceways. Reducing this axial play does two things. It improves the repeatability of the screw assembly — meaning the assembly […]
How roller-screw and ball-screw actuators compare in high-force applications
As electric rod-style actuators overtake fluid power in a variety of high-force applications, it is important to understand how different screw technologies compare in the search for optimum performance and low life-cycle cost. By Daniel Schmit • Product Manager | Tolomatic Inc. Electric-rod actuators with either roller-screw or ball-screw technology are playing an expanding role […]
Bearing damage: What’s the difference between brinelling, spalling, and fretting?
Bearing damage, and ultimately, failure, can be caused by a variety of conditions, including improper mounting, poor lubrication, and overloading, to name a few. The mode of damage — what actually happened to the bearing as a result of detrimental conditions — is characterized by visible features, such as discoloration, wear marks, or pitting, on […]
Exlar GTX now with Hiperface DSL Stegmann absolute encoders
Curtiss-Wright Corporation’s Industrial Division announced that its Exlar facility, located in Chanhassen, MN, has added Hiperface DSL Stegmann absolute encoders as a part of their available Rockwell Automation feedback options. The GTX series joined the Exlar TTX, Tritex II, GSX, FTX, and K series Encompass product families in 2018. As an Encompass Partner, Curtiss-Wright and Rockwell […]
Using software for designing and sizing motion-control systems
Today servomotors abound. Thankfully the art of using speed, torque, and inertia to select from these servomotor offerings for specific applications has become quite automated. By Sixto Moralez • Regional motion engineer | Yaskawa America Inc. Drives & Motion Div. Now, certain sizing and selecting software only requires that design engineers enter a minimum of […]
Why use linear guides and ball screws with ball chains?
One of the differences between radial ball bearings and recirculating ball linear guides has historically been that radial bearings typically use a cage to separate the balls and control their movement, whereas profiled rail guides did not. But in the early 2000’s, manufacturers of profiled rail bearings began introducing versions with ball cages (also referred […]
